1. Field
This application relates generally to mold vibrators for concrete product molding machines.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Molds for concrete product molding machines are vibrated to provide better filling of the mold. Mold vibration also assists the formation of denser concrete products by allowing the concrete to settle to a more structurally sound state. Some concrete product molding machines include a frame, and a mold assembly carried by the frame. A pallet and pallet receiver of the concrete product molding machine are raised to pick-up the mold assembly from a rest position and raise it to an elevated vibration position approximately ⅝ inch above the rest position. Two unbalanced vibrator shafts are carried by the mold assembly and are supported for rotation about respective parallel vibrator shaft axes, each vibrator shaft axis being displaced from a center of mass of that vibrator shaft so that each vibrator shaft produces off-axis force when rotated about its vibrator shaft axis. The vibrator shafts are driven in rotation by respective vibration drives comprising electric drive motors, belts, and pulleys. A concrete product molding machine of this type is disclosed, at least in part, in U.S. Pat. No. 4,978,488 issued Dec. 18, 1990 to Wallace, which is incorporated herein in its entirety, by reference.